Andy_K 

i think it’s a 1976 model. That’s partly based on a story from the guy I got it from (and eventually gave it back to) about when his brother originally bought it, but I think I had another reason for thinking it. I don’t remember what that reason was.

Pompiere

That looks like the road going version of the Ford Tri Motor.

Kabuki12

I think a lot of us C&V folks also appreciate the other classic vehicles . This thread has brought out some great images that I have enjoyed tremendously, thanks.

scarlson 

The problem with this is, I just don't think the hand hammered look ever represented hand craft, in bicycle fenders at least. Hammered aluminum bike fenders came out in the '30s or '40s, same time as your streamline toaster. They were always made by machine, as far as I know. The modern ones are reproductions or homages to these, not anything earlier. These '30s and '40s hammered fenders were part of a product lineup that included fluted fenders, smooth fenders, and fenders that had polygonal facets, called "zeppelins" by some because they resembled the Zeppelin's polygonal cross-section. Maybe these Zeppelins would be more amenable to your modernist streamlined aesthetic?


Funny enough, the French company Lefol made a Zeppelin style fender, but possibly because of anti-krautism, they called it "Le Paon" (the peacock).

The first saddles with hammered rivets were "butchered" saddles. It wasn't all about softening the leather, although you could get that done. It was more about customizing. Professionals and other performance-inclined individuals would give a stock saddle (which came with machine-done steel rivets) to someone to butcher. Could be a leatherworker, cobbler, or whatever. This guy would lighten the saddle and give it a custom shape that could be better for the individual who ordered the butchery. The leather would be taken off, the saddle frame possibly altered, the leather chopped and reshaped, and then the whole thing needed to be put back together, which would be done by hand. This is where the hand hammered rivets came in. They were easier to do and possibly better at holding the leather on. And on a small scale like a cobbler's shop or bike shop doing one-off saddle butchery, they didn't cost any more than buying steel rivets and a setting die, which you'd need for steel rivets.

This is my example of a butchered saddle. I think it's from the '50s or so. It started out as a B17, as evidenced by the markings on the leather, so I have placed a stock B17 next to it for scale. The cantle plate shows evidence of being hammered inwards to reduce the width. The leather curls inward under it even without lacing. It is surprisingly comfortable for how it looks. And lighter than any other leather saddle I have, in spite of its steel rails.


So having hand-hammered rivets was a sign of high-performance gear.

mstateglfr 

I cant believe I just watched that, but the guy was mesmerizing for some reason.

cudak888 

This. I have not ever seen a single hand-hammered bike fender from BITD. It's always been machine made.

I can only assume that besides appearance, the patterns may have helped with structural strength, similar to how the stampings on the Citroën van help strengthen the otherwise light and floppy steel. Same reason fender edges are rolled over. Sure, it helps to reduce sharp edges, but a plain aluminum fender would be very noodly without it.



Pic via @THREADLESS1430 at: https://flic.kr/p/mWtGae - really hard to find this picture due to Flickr not being indexed by Google.

-Kurt

Kabuki12

I do like the hammered look on my Brooks Team Pro with the oversized rivets. ^ those fenders are works of art , even if machine generated.....luv 'em!

Hondo6

I'd guess corrugated steel was used in aircraft work of that era because the corrugations make it stronger in one direction (the direction perpendicular to the corrugations) than an equivalent flat sheet, thus potentially allowing the use of thinner steel - and aircraft engines of the day were still (by a decade or two later's standards) not particularly high-performers. With proper design and given the flight speeds of the day, that might have resulted in a significant weight savings.

I'd guess the reasons for use on the vans pictured later were much the same, particularly if those date to the 1940s or early 1950s (not that familiar with those vehicles). I've read that for a while immediately after World War II, France was severely short in certain structural materials.

The corrugations were oriented in the direction of travel presumably to avoid dramatically increasing wind resistance.

scarlson 

It was aluminum, not steel, but you are more or less right. Junkers started making corrugated designs in late WWI, when the engines were even less powerful, and speeds were even lower. Because drag increases with the square of speed, at 100mph the corrugations barely mattered while at 200mph they matter more than a bit more! In addition, the low power of the engines of that time demanded low wing loadings, so surface friction was a minor contribution to the overall drag of aircraft of this time.
By 1932, when the Ju-52 flew first, this technique was already past its prime. Engine performance, construction techniques and wing loading had improved to a point that the better solution was to rivet stiffeners on the inside of a load-carrying skin. Junkers airplanes were very innovative first, but once the company had found a good way of producing robust, low-cost aircraft, it stuck to what it knew. However, Junkers' concept of a steel or aluminum truss plus the corrugated aluminum skin was heavier than the smooth monocoque skin which we still use on today's airplanes, and once aerodynamic drag could be reduced to a point where the drag increase due to the larger wetted surface of the corrugated skin could not be overlooked, even Junkers switched over to smooth skin.

The reason for corrugated steel's use on the Citroën HY van was because it was not like a traditional van of that era. Instead of being body-on-frame construction, it was unibody, like a modern car, giving it a very low loading floor and center of gravity, as well as mechanical simplicity. Unibody construction led to the skin bearing significant load. The van was powered by the same 2L 4-cylinder engine found in the Traction Avant, so weight was also a consideration. To save weight (and cost) and go with a thinner gauge of steel, corrugation was chosen to stiffen the structure. This is why it weighed only 1200kg but could carry 1600kg. Thanks to the stiff construction and welds holding the metal together, the floor inside was strong enough to support a horse or cow.

steelbikeguy

I'd never bothered to look into Rimowa, but now that I take a look at their web site, and especially their "Original" family of luggage, I can see why they could afford to fly a vintage airplane around as advertising! $1325 (and up) for a roll-on piece of luggage. wow... now I feel much better about what I've spent on custom bike frames.

Looking further on their site, I see that I can get a small piece of luggage for carrying a wine or champagne bottle... for only $1820. It makes a NOS T.A. bottle cage seem like an absolute bargain by comparison.

I should say that the folks who own and operate vintage aircraft are already shoveling large sums of money to keep those aircraft flying, so they probably are a great target market for this sort of prestige luggage.

Steve in Peoria

Hondo6

Thanks for the info. It's always good to learn something new - and I just did.

Chombi1 

The corrugations on the Ford Trimotor and other planes from that era gave the fuselage and wings additional stiffness.
it might have resulted in less internal framing for tye plane = lighter.

SurferRosa

Wonder if this was used on prisoners at Abu Ghraib.

steelbikeguy

Yep, it seems fairly obvious that the corrugations were for stiffness.
I had to look up the Wiki page for the Trimotor to get the basics.... it was designed sometime before 1925, so I guess they were still figuring out the best ways to construct an all-metal aircraft. It looks like they hadn't figured out that they should be running the control cables inside the fuselage either.

This construction was a change from the old method of just putting cloth over the aircraft's framework. The old airframe construction was pretty fascinating all by itself... Wood beams to create a box-like frame skeleton with tensioned bracing wires running diagonally across the box elements. I saw a great display of a JN-4 "Jenny" biplane that showed off the construction. The cloth skin was gone, and the aircraft was displayed in a tent and labeled "Naked Jenny".







The amount of hand work involved in creating all of those structural elements must have been immense!
No idea of how many hammers were used in this type of construction (just to bring this back to the original topic, sorta).

Steve in Peoria

Chombi1 

Copper pots must been hand hammered to make the pot stronger/stiffer as copper is quite soft.
It kinda makes sense then to do he same to an aluminum fender on a bike.

semroc

Fenders? Pffft, not in this lifetime. Great pics in this thread.

AdventureManCO 

Thanks; would love to check it out.

Bianchigirll 

It was probably the best infomercial ever made. He was selling something by giving you a history lesson and showing how to use it rather than just shouting about how great it and the price. This was all over TV in the late ‘89s

Schweinhund

Hammer hammer

cudak888 

This Bottecchia was supposed to get Lefol hammered fenders, but a snafu of shipping and a lucky opportunity via nlerner meant it wound up with plebian Honjo Turtles.

I hope this meets with the OP's approval. If it doesn't, I can provide a pantographed Colnago kickstand as a prayer offering.



-Kurt

scarlson 

Griswold! You are a man of culture, I see
There is nothing like frying in a good piece of American iron.

Schweinhund

I have 18 vintage and antique American frying pans, as well as one French pan along with 3 Dutch ovens like the hammered one I posted. I'm an equal opportunity hoarder.
They are awesome when you use them with gas and even better with induction heating

scarlson 

I love them even with our lousy apartment electric coil stove. The light weight and smooth surface are a revelation after using the modern stuff. I inherited my two Griswold frying pans (one prewar large logo and one postwar small logo) from my grandpa's cousin when he died. They were going to auction them off but I nabbed them along with some of his cuckoo clock collection.

Bianchigirll 

Interestingly a few decades after those seemingly primitive, but beautiful in their own way, tri-motors took to the sky’s the vaunted A-12s and SR-71s also featured corrugated skin panels to assist in heat dissipation and expansion and contraction. I suspect some very large hydraulic hammers beat these into submission




Somewhere in all the documentaries and books I seen on WWII there are pics and even I believe film of German paratroopers riding on the wings of Fokker Tri-motors.

dedhed

I sold this guy some of my grandfather's blacksmith tools when he was starting out now he hand hammers hammers.

https://www.cergolforge.com/?variant=40204869501017